1. Methods for Burden. Assessment: Echinococcosis. Paul Torgerson. Universität Zürich. Institut für Parasitologie. Page 2. 2. Highly Endemic. Endemic. Sporadic.
Methods for Burden Assessment: Echinococcosis
Paul Torgerson Universität Zürich Institut für Parasitologie
1
F F F
Highly Endemic
Endemic F: Free PF: Provisionally Free
PF Sporadic
2
PF OO
3
Methods of burden assessment • Economic modelling techniques • Financial estimates – Zoonoses – Animal and human health costs
• Non financial estimates – Levels the playing field between chronic and acute disease – Human life has the same value in rich and poor countries – WHO preferred instrument is the DALY
• Used to compare different disease burdens and hence drive policy • Developed stochastic techniques to model the uncertainty of source data
4
Economics Costs-Livestock
Animal production losses Decreased food conversion efficiency Mortality or morbidity Lower reproductive performance Lower milk yield
5
Economics Costs-Human Disease
Cost of Treatment – – –
Surgery Medical treatment Convalescence
Morbidity
– Time off work – Less productive
Mortality
– Economic effects of death 6
Data Sources
OIE reports – Gross underreporting
Literature reports – Method of collection – Biased
Representative surveys
7
OIE Data Country
2003
2002
2001
2000
Albania Belarus
1999
1998
1997
1996
6 8
11
55
Bolivia
5
Bosnia & Herzegovina
34
24
13
3
Bulgaria
639
684
628
662
691
14
21
8
591
Italy Jordan
2
Kenya
18
Kyrgystan Lithuania
2
Palestinian Auth.
10
470
477
566
573
4
4
4
1
4
4
Peru
1,326
Sudan
9
Syria
24
Tunisia
100
Uzbekistan
8
162
157
196
154
227
285
299
1,428
1,321
1,130
976
8
Data from literature Country
Years evaluated
Human incidence (annual incidence per 100,000 pop.)
Reference
Austria
1983-1992
0.21-0.67
Australia
1991-1994
0.23
Corsica
1966-1970
10
Economides and Thrasou, 1999
Greece
1994
3.4
Economides and Thrasou, 1999
Italy (Entire)
1980-1984
1.92
Gabriele et al., 1997
Italy (regional)
Early 2000s
9.7-Sardinia 1.57- Emilia Ranagna 2.30-Sicily 2.33-Apulia
Gabriele et al., 2004
Portugal
1998-2000
1.82
Seimenis, 2003
1996
0.9
Garcia, 1997
Switzerland
1984-1992
0.38 (0.09- Swiss nationals 1.39- foreigners)
Eckert et al., 1995
U.K. (Powys)
1984-1990
2.3
Lloyd et al., 1998
Spain
Auer and Aspöck, 1993 Longbottom and Hargreaves, 1995
9
Sources of Data Uzbekistan
OIE reports – 1999 - 1428 cases – 2002 - 1500
Government figures – 2000 – 1435 cases – 2001 - 819
Hospital records search and case finding1 – 2000 – 4636 cases – 2001 – 4089 cases 1.
10
Nazirov et al. (2002) Echinococcosis in Uzbekistan: types of problems and methods to improve traetment Uzbek Medical Journal 2-3, pp 2-5 (in Russian)
Sources of Data Jordan
OIE reports – 1996-2004 – 0-21 cases per year
Hospital records search and case finding – 1995 – c 128 cases per year
11
Uncertainty
Some costs well defined Other costs ?? – May represent the largest losses
Poor or inadequate reporting Sample size Diagnostic test efficiency Attributable morbidity Monte-Carlo techniques – Randomly vary each “unknown” 12
Estimating unknown Data
30000 y = 1.5476x R2 = 0.8927
Per Capita GNI
25000 20000 15000 10000 5000 0 0
2000
4000
6000
8000
10000 12000 14000 16000
Cost of Treatment
For Global Burden Estimates : Cost of treatment in each country varied as the linear predictor (mean + SEM) 13
Estimating unknown data
Other modelling techniques From published prevalence in – Dogs c 10% – Sheep c 50%
Estimate Incidence in humans – c10 cases/100,000/year – Over estimates some (eg Muslim) – Under estimates eg Chinese 14
Hospital Costs
Cost of treatment and medication
Annual number of cases~mean (+SEM) x Cost of representative sample~mean (+SEM) 15
525.38
597.03
668.68
740.32
811.97
Cost of Treatm ent
X 743.27
846.52
949.77
1,053.02
1,156.27
Num ber of cases
= 437,891.93
544,197.65
650,503.37
756,809.09
863,114.81
Total Treatm ent Costs
95% CIs
16
Other Human Health Costs
Long term ill health Do patients fully recover? Perhaps not? Permanent decrease in quality of life. – How much? – Needs good studies to accurately define Infected but not treated – Sub clinical disease Some patients die! – Capital Approach – Willingness to pay
Infected people are poorer!
17
Echinococcosis in Jordan Total Costs Relative probability
Human health cost Animal health cost Total Cost
0
2,500 ,00 0
5,000 ,000
7,500 ,000
10 ,000,000
Cost ($US millions) All calculations should be discounted for future values
18
Non financial instruments
HALYs, DALYs, QALYs All measures of loss of health WHO preferred measure is DALY – Disability Adjusted Life Year – Measures number of “years of full health” lost due to disease
19
DALY
Length of time lived with morbidity Discounted for – Disability weight – Age of onset – Losses in future years at today’s rates
Numbers of healthy years lost
20
Morbidity costs SF-12 results - China 25.00
Mean Score
20.00
15.00 Control Echinococcosis Pos.
10.00
5.00
0.00 Phys ical Com pone nt Sum m ary
M e ntal Com pone nt Sum m ary 21
Country (Year)
Number of patients
Cure
Morbidity
Relapse
Greece (1984-1990)
56
40 (72%)
13 (23%)
3 (5%)
0 (0%)
(14)
Italy (1950-1987)
298
244 (82%)
27 (9%)
15 (5%)
12 (4%)
(15)
Turkey (1992-1999)
95
32 (34%)
38 (40%)
24 (25%)
1 (1%)
(16)
Turkey (1990-1995)
108
88 (81%)
19 (18%)
0 (0%)
1 (1%)
(17)
Greece (1985-1990)
67
59 (86%)
4 (6%)
3 (6%)
1 (2%)
(18)
Italy (1982-1994)
89
70 (79%)
17 (19%)
1 (1%)
1 (1%)
(19)
Total
713
533 (75%)
118 (17%)
46 (6%)
16 (2%)
Death
Reference
22
Disability Weights
Echinococcosis Disease free liver cancer (0.200) (improve after surgery) Preterminal liver cancer (0.239) (Post surgical conditions) Terminal liver cancer (0.809) (Recurrent disease, multiorgans etc) Death 1 Weights and duration assigned using a multinomial distribution with relative proportions based on published surgical studies.
23
Years
Average age of onset/detection
Reference
China
2001-2003
35
(3)
Jordan
1994-2000
31-45
(22)
1980s
21-30
(23)
Morocco
2000-2001
32
(24)
Turkey
1992-1999
44
(16)
Uruguay
1991-1992
45
(25)
Kyrgystan
1991-2000
22
(26)
Country
Kenya (Turkana)
24
c 0.81 DALYs lost per person >74,000
72,001 - 74,000
70,001 - 72,000
68,001 - 70,000
66,001 - 68,000
64,001 - 66,000
62,001 - 64,000
60,001 - 62,000
58,001 - 60,000
56,001 - 58,000
54,001 - 56,000
52,001 - 54,000
50,001 - 52,000
48,001 - 50,000
46,001 - 48,000
44,001 - 46,000
42,001 - 44,000
40,001 - 42,000
38,001 - 40,000
36,001 - 38,000
34,001 - 36,000
< 34,000
Probability
DALYs lost in Serchu, China county due to echinococcosis
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
DALYS lost
25
Economic losses
Attributable loses only True losses are only those that are preventable Cystic echinococcosis and cysticercosis – Eliminated by veterinary public health programmes – Essentially entire burden is preventable
26
Global Burden of Echinococcosis
US$4.1 Billion (adjusted for underreporting, PPE estimate) 54% Human costs – >1.0 million DALYs – c 200,000 cases per year
46% Animal health costs
27
DALYs Leprosy
199,000
Onchocerciasis
484,000
Dengue
616,000
Chagas
667,000
Cystic echinococcosis
1,079,038
Trypanosomiasis
1,525,000
Schistosomiasis
1,702,000
Leishmaniasis
2,090,000
Lymphatic filariasis
5,777,000
TB
34,736,000
Malaria
46,486,000
Japanese encephalitis
709,000
Trachoma
2,329,000
Ascariasis
1,817,000
Trichuriasis
1,006,000
Hookworm
59,000 28
Conclusions
Financial estimates estimate total burden of disease including animal health costs Purchasing power equivalents give a better idea of disease burden in poor countries Such results can be used to implement cost sharing between sectors DALYs for zoonoses can indicate priorities compared to other diseases Results of cost sharing can indicate the true cost benefit to health services Stochastic and risk analysis techniques are powerful tools to model uncertainty. 29
Thank You
Dr Christine Budke National Institutes of Health (U.S.A.) and the National Science Foundation (U.S.A.) (Ecology of Infectious Diseases Programme) European Union INTAS Swiss National Science Funds 30
Numbers of surgical cases of cystic echinococcosis Kazakhstan 1984-2001
800
400
0 1984
1988 USSR
СССР
1992
1996
2001
Kazakhstan
Казакхстан 31
